An Overview of Building Green
BUILT GREEN FEATURES:
The following is a list of a few of the green features and building practices promoted in the Built Green program:
- Energy Efficiency
- Indoor Air Quality
- Conserving Natural Resources
- Water Quality
- Energy Efficiency
Advanced Framing/Extra Insulation
Advanced framing is a technique used by builders help reduce construction costs and increase energy savings. On average, advanced framing uses 30% less lumber, takes less time to construct, and costs less to build because the reduced use of lumber more than offsets the additional cost of extra insulation. Construction cost savings is estimated at $0.29 per square foot of wall area. Total savings for this measure alone are 2 to 4% of total energy use.
High Efficiency Water Heater
Locating the hot water heater near the point of highest use will minimize pipeline energy loss. Typically, the point of highest demand is the shower. Another strategy designed to increase efficiency is to insulate hot and cold water pipes within 3 feet of the hot water heater. This measure reduces standby heat loss from the water tank. The tank continuously heats the piping and the water in it even when no water is being used. The pipes act as cooling rods. Insulating them reduces the rate of heat loss. In addition, choosing a high efficiency water heater can save energy and water.
Efficient Household Appliances
Built Green homes feature appliances that are as energy efficient as possible. The reduced costs associated with operating energy efficient appliances offset any higher initial costs of purchasing the appliances. Builders are encouraged to use appliances that have Energy Guide or Energy Star labels to insure that they meet energy efficient criteria.
Advanced caulking is part of the airtight drywall approach (ADA) for framed structures, which is an advanced sealing package that goes beyond basic practice. Specifically, caulk or gasket drywall is installed on exterior walls at the top and bottom plates, windows and doorframes. Caulk or gasket drywall is used on interior walls at intersections with exterior ceilings. Caulk or gasket drywall is used at electrical, plumbing or mechanical penetrations in the drywall.
INDOOR AIR QUALITY:
Using low-pile or less allergen-attracting carpet and pad can greatly improve indoor air quality. Installing carpeting by tacking rather than using glue also reduces air pollutants. There are also natural fiber carpets available such as jute, sisal and wool that many builders offer to improve air quality. Many Built Green homes feature plans that reduce the amount of carpeting and use alternate flooring made from sustainably harvested wood or bamboo.
Many Built Green homes use low-VOC and low-toxic interior paints and finishes to reduce toxins ordinarily associated with other paints. Using these types of paints helps to improve the overall indoor air quality of the home.
Greater air tightness creates a need for mechanical ventilation to avoid potential indoor air quality problems. Balanced or slightly positive ventilation keeps outdoor pollutants from being drawn into the house, prevents backdrafting or spillage from combustion appliances (due to under-pressurization), and prevents moisture migration into structural cavities (due to over-pressurization). Ventilation can be provided by quiet fans with automatic controls or by heat recovery ventilators. In a balanced system, air brought indoors by one fan is exhausted outdoors at the same rate by another fan. In a slightly positive system, air brought indoors is exhausted outdoors at a slightly slower rate. It is important to avoid over-pressurizing the building, which will force moisture into and through walls and other structural cavities. To get a slightly positive air pressure you must adjust supply ventilation slightly higher than exhaust ventilation (if exhaust is provided). If you are not sure you can maintain a slightly positive pressure without over-pressurizing the building, it is best to seek a balanced pressurization.
CONSERVING NATURAL RESOURCES:
There are many manufacturers of plastic lumber nationwide. Recycled plastic lumber or plastic/wood composite lumber provide durable alternatives to solid wood for exterior applications such as fences, benches, decking, docks, retaining walls, picnic tables, and landscape borders. Due to its weather-and insect-resistant nature, plastic lumber can readily substitute for treated wood in non-structural applications. Plastic lumber is also rot and corrosion-proof, and will not crack, splinter, or chip. It has a long life expectancy in exposed, sub-grade or marine applications, and does not leach chemicals into ground or surface water or soil as treated wood can.
Plastic lumber resists vandalism and does not require painting. It is available in a variety of colors,including white, although many companies have a standard color of either brown or black. These products can be nailed, screwed, sanded, glued, or turned on a lathe with standard woodworking tools. One challenging aspect of working with plastic lumber is its high expansion coefficient, which must be considered during installation. Check with the manufacturer regarding structural support specifications.
There is a large family of engineered structural products, including laminated veneer lumber (LVL), wood I-beams and I-joists, and wood roof and floor trusses. These products combine efficient raw material use with improved strength and performance capabilities to produce a superior option to traditional materials. Engineered lumber manufacturers use fast-growing, small-diameter trees efficiently. Combining wood veneer and fiber with adhesives produces laminated veneer lumber. The LVL manufacturing process allows more of the log (up to 80%) to end up as product. LVL lumber is very consistent and stable. Wood I-beams and I-joists also combine veneer and adhesives.
LVL headers and I-beams are accepted by all major building codes. They provide more load-bearing capacity than solid sawn lumber, and resist shrinking, twisting, splitting, warping, and crowning. They are capable of long spans, thereby increasing design flexibility. They can cost more than dimensional lumber, but in general are considered better products. The American Plywood Association estimated that in 1998 I-joists alone accounted for over a third of all residential floor joists installed in the U.S. Wood roof and floor trusses are commonly used instead of cut rafters because they save both time and materials. They can also reduce wood waste because, ideally, you order only what you need, and because of efficiencies in the production process.
Fiber Cement Siding
Fiber-cement composites are resource-efficient, and in addition to durability and low maintenance, offer a very good fire rating when compared to wood or metal siding. The wood fiber in these products is reclaimed from wood processing waste. It can also be harvested from small diameter fast-growing species. Minimizing the need to replace any siding product offers a maximum consumer benefit to the homeowner, in addition to the obvious environmental impact. Many of the fiber-cement composites offer a 50-year warranty.
The process of extracting lay for brick production is fairly benign, and results in very little wasted material. Brick is often used close to its manufacturing site. It has an almost limitless life-span and can be recycled or salvaged for use after demolition. Brick is also a recyclable material that can be crushed and either returned to the manufacturing process, or used as a landscaping material in its crushed form.
Building Materials and Food Recycling
Built Green builders and remodelers recycle as much as possible of scrap building materials and post a jobsite recycling plan to decrease the amount of materials going to our already overburdened landfills. Building materials such as lumber, wall board, concrete, cardboard, ceiling tiles, paints and packaging can often be recycled. If a remodeler or builder is deconstructing an existing building on the site, many of those materials can also be salvaged or recycled including wood flooring, framing materials, brick, ceramic tile and stone, trim and cabinetry, among others. Our builders also facilitate homeowner recycling by installing recycling bins in kitchens or garages. Also, food recycling chutes are an alternative to traditional food garbage disposals that many builders include to provide homeowners with an easy way to compost food waste.
WATER QUALITY PROTECTION:
Porous Paving Schemes
The goal of this strategy is to reduce or eliminate runoff due to impervious (watertight) surfaces. Minimizing or eliminating impervious surfaces by designing driveways, walkways, and patios that allow stormwater runoff to infiltrate into the ground minimizes the impact on aquatic systems. Uncompacted gravel, crushed stone and open or porous paving blocks can be used for walkways and other light traffic areas.
Rainwater collected from the roof is a free source of landscape irrigation water. These systems can reduce outdoor water usage, thereby reducing the homeowner’s water consumption. Rainwater can also be harvested from soil surfaces and outdoor paved surfaces. These systems are designed to provide water for irrigation and are not intended for potable (drinking) use. A rooftop rainwater collection system consists of a suitable roof and guttering system, a storage tank(s), and a simple filtration system. Cistern or tank storage is sized for the rainfall amount and roof size, with appropriate overflow devices. Cisterns can be made of concrete, ferro-cement, stone, or prefabricated metal, plastic, or fiberglass and use only watertight, opaque materials.
Low Impact Development
Low Impact Development (LID) is an innovative approach to stormwater management that uses nature as its model, and in the process can help protect streams, fish and wildlife habitat, wetlands, shellfish growing areas, and drinking water supplies. Basically, LID’s goal is to mimic a site’s predevelopment hydrology by using design techniques that infiltrate, filter, store, evaporate, and detain rainwater runoff close to its source. Instead of disposing and treating stormwater in large, costly end-of-pipe facilities located at the bottom of drainage areas, LID addresses stormwater through small, cost-effective landscape features located at the lot level. LID features can include many components of the urban environment such as open space, vegetated rooftops, reduced street widths and curbs, streetscapes, pervious parking lots and sidewalks, medians and other buffer zones using more vegetation. These LID practices can potentially increase developable land for large or small developers by reducing size requirements for stormwater ponds, and also lower infrastructure costs. LID can be applied to new development, urban retrofits, and redevelopment projects.